Microelectronic devices, such as semiconductor devices and field emission displays, are typically fabricated on and/or in microelectronic workpieces using several different types of process machines or tools. A workpiece, for example, is often processed using tools for depositing, implanting, diffusing, doping, etching, polishing/planarizing, and patterning materials. A workpiece typically undergoes several processing steps within a single enclosed clean or “mini” environment within a processing tool. For example, microelectronic workpieces are typically plated with a conductive material, etched, annealed and cleaned, using a plurality of processing stations all housed within a single processing enclosure that defines a clean mini environment.
The foregoing processes can be performed on each workpiece individually in separate single-wafer processing stations, and the workpieces can be moved from one processing station to the next, a technique referred to in the industry as single-wafer processing. One initial problem encountered with single-wafer processing was determining how to deliver individual workpieces to and from the enclosure while maintaining a clean environment within the enclosure. One approach to addressing this problem has been to load several workpieces in a portable container while the container is in a clean environment, and then seal the container with a removable door. Accordingly, the interior of the container can define another clean mini environment. The door is then removed when the container is flush with a hatch of the processing enclosure to reduce the likelihood for introducing contaminants into the enclosure.
FIG. 1 illustrates a conventional container 20 having a Front Opening Unified Pod (FOUP) design in accordance with the prior art. The container 20 supports a plurality of microelectronic workpieces 21 and has a door 23 that is removed for access to the interior of the container 20. The container 20 is supported relative to a processing tool (not shown) on a container support 30. The container support 30 has a shroud 31 with openings 33 through which support pins 34 and a latch pin 40 project to engage and secure the container 20 to the container support 30.
In one aspect of the arrangement shown in FIG. 1, the latch pin 40 includes outwardly extending arms 41, each of which has a downwardly facing, circumferentially extending declined plane. The arms 41 project through a corresponding aperture in the bottom of the container 20 when the container 20 is placed on the shroud 31. As the latch pin 40 rotates in the direction indicated by arrow A, the downwardly facing declined planes begin to engage an upwardly facing surface in the aperture at the base of the container 20. Because the downwardly facing surfaces of the arms 41 are in declined, the latch pin 40 draws the container 20 downwardly toward the support pins 34 as the latch pin 40 rotates, to secure the container 20 to the container support 30.
One drawback with the foregoing design described above with reference to FIG. 1 is that the manufacturing tolerances for the container 20, and in particular, the portion of the container 20 engaged by the latch pin 40, must be very tight for the latch pin 40 to properly secure the container. For example, if the base of the container is slightly warped, the latch pin 40 may be unable to properly engage the aperture in the base, or may only loosely contact the upwardly facing surface within the aperture. If the container 20 is not properly secured on the container support 30, it can be jarred or otherwise misaligned, which can cause damage to the microelectronic workpieces 21 when automatic devices attempt to load or unload the container 20.